Mercedes sold a record 120,510 units in June, a rise of 6.4 percent, topping Audi, which saw June sales grew 19 percent to 117,650 cars last month.

BMW brand's global deliveries, boosted by sales of the new 5-series sedan and X3 SUV, rose 17.8 percent to 689,861 units in the first six months of the year, ahead of Audi's 17.7 percent rise to 652,950 cars. Mercedes' sales grew 9.7 percent to 610,531 through six months.

"The figures reflect strong global demand," BMW sales and marketing boss Ian Robertson said in a statement, adding however, that due to the model cycle and the year-on-year base effects, he expects the carmaker's growth to slow in the second half of the year.

In total, BMW Group, including the BMW, Mini and Rolls-Royce brands, sold 165,855 units in June, a rise of 15.9 percent. Between January and June, the brands' sales were 833,366, a rise of 19.7 percent.

China, U.S. sales

Luxury carmakers have achieved huge sales gain in China thanks to the country's growing population of super-rich. But China's car market is expected to cool this year after surging by a third to a record high in 2010.

BMW Group's six-month sales in China jumped 61 percent to 121,614 vehicles. Mercedes and its Smart brand sold 92,174 units in China in the first half, up 52 percent from the same period last year. Meanwhile, Audi continued to be the dominant luxury brand in the world's largest market with sales of 140,699 cars in China in the first half, 28 percent more than in the first half of 2010.

Through six months, Germany is BMW Group's top global sales market with a volume of 149,786 cars, a rise of 10.6 percent. Germany edged BMW Group's second-biggest market, the United States, where the carmaker's sales were up 18 percent to 143,521 units between January and June. Audi's volume in Germany rose 16 percent to 125,091 and its U.S. sales increased 15 percent in the half to 55,909. Mercedes' U.S. sales rose 7 percent to 110,926 in the first half while sales in Germany edged up less than a percent to 123,013 units in the first half.